Porous cellulose composite aerogel films with super piezoelectric properties for energy harvesting

& nbsp;The piezoelectric effect is one of the most promising electromechanical coupling processes for mechanical energy conversion and energy harvesting. However, natural polymer based piezoelectric materials are of poor piezo-electric performance. we developed flexible porous piezoelectric aerogel films based on TEMPO-oxidized cellulose nanofibrils (TOCN) and Mo-S2 nanosheets. Those aerogel films possessed large specific surface areas and abundant mesopores. Moreover, they exhibited very good piezoelectric properties when a field strength of 20 MV/m was used to polarize MoS2 nanosheets and air in the mesopores. When assembled to piezoelectric nanogenerators (PENGs), a TOCN/MoS2 aerogel film PENG containing 6 wt% of MoS2 exhibited the best output performance. It generated an open circuit voltage of 42 V and a short-circuit current of 1.1 mu A, a maximum area power density of 1.29 mu W/cm(2) and a maximum volume power density of 0.143 mu W/cm(3). These features enable them to be promising piezoelectric materials for energy harvesting.